mcratchet1

Ok thanks I’ll give them a shout

I have a 2013 mru 613 the small radiator that sets behind driver side is leaking on the seams. Does anyone know a good aftermarket one or a good place to buy salvage? For a new one Mack wants $5500.00 this blows my mind. It’s 18”x36”part #21199385 thanks!

I’m assuming this is probably an ecu issue ? 

On 1/30/2025 at 10:40 AM, Mackpro said:

Is it a MR or a MRU ? Find the air line going to the fan clutch and put air directly to the clutch and see if it unlocks . There should be an air solinoid that controls the air to the fan. If it’s a MR  fuse 41 supply’s 12 volts to this solinoid. This fuse in in the fuse box that’s outside of the cab. Also the green high pressure switch for the AC could be bad or unplugged causing the ECM to turn on the fan . 

So I changed that green ac switch the fan is now working properly. But now if you turn ac on the fan stays engaged all day

No it’s not broke but yes seems to wobble when clutch is engaged. The problem I’m having is it stays engaged 75% of the time. As soon as I leave in the morning 

Ok finally checked it out blowing air does dis engage clutch. I have air going into that air switch but no air coming out. I have power but no ground.  When I add a ground everything works. Checked wire to harness I do not see any issues. Does anyone know where the ground comes from? Also does that air switch disengage with ground or power? I also added a video does it look like clutch has to much wobble?

No when I shut off key fan stop almost immediately. That’s with clutch disengage. Also when I unplugged ac line switch the clutch engaged. The truck is cold so it should not engage. 

Ok finally checked it out blowing air does dis engage clutch. I have air going into that air switch but no air coming out. I have power but no ground.  When I add a ground everything works. Checked wire to harness I do not see any issues. Does anyone know where the ground comes from? Also does that air switch disengage with ground or power? I also added a video does it look like clutch has to much wobble?

Sorry it is an mr688s it’s off in the morning for just a few mins then stays engaged the rest of day until just idling at shop but temp never goes over 180 if I remember correctly it only engages when temp hits 200

I have an 07 mr688s with a Horton pneumatic fan clutch. Having issues with it constantly staying engaged. What’s the best way to diagnose if it’s a faulty sensor or bad clutch? Thanks in advance 

Ok got it I’ll clean it up and pull top cover of transmission thanks

Just to clarify the cover we’re talking about removing is on the back side above yoke? Four bolts to remove, I tried to pull that one off but does not want to move back. Didn’t want to try to pry it off. Never removed that one before is it ok to tap it back with a rubber mallet?

Is this it under back cover the attached pic

Yes I flip the button before taking it out of high gear to go into low. I tried it in neutral as well no difference 

No I did not is there orings inside that cover?

or what should I look for

The range button moves good I did not see any kinks. It does not do this all the time but probably 5-6 times a day

Yes I can hear it shift but when I take off in low gear sometimes it does not grab a gear like it’s in neutral. It’s not shifting all the way to low gears. I can flip the button back and forth and hear it though

Hello I have a 2013 mru 613 with T310 10 speed tranny. Couple times a time I cannot get it to switch to low gears. When I stop sometime I toggle gear switch up and down then I can. Other times no luck and I take off in 6 gear. I replaced hi/lo valve thinking maybe internal leak but no change. Also new oil, check for air leaks nothing . Does this sound like an internal problem. Any help would be really appreciated 

Yes exhaust valve up on #2. I got it, I  just did not snug down enough on exhaust valve to put enough pressure down on spring. Once I did that she’s running great. Thanks for all the quick help! I really appreciate it!!

Ok so push down on the springs and set the exhaust . Just push springs down by hand?

I made sure I was on right one stared on 1&6 

6 was tight 1 both were loose and push tubes were close to being even

Yes I did that I guess my question is on exhaust push rod that has spring do I need to compress spring then check exhaust or leave spring alone

I have 03 Mack mr688s 350hp

i had to replace #1 injector the push rods on exhaust side has springs on top of them. I have never seen this before. So I adjusted intake and exhaust as normal. But I have a rattle now so they must be to loose. Is there a certain way to adjust them with those springs? Any help would be appreciated 

No i did not

Just had a question I have 07 mr688s cab over lately I’ll get no response to pedal for a split second while driving it always happens around 1300-1600 rpm’s it was maybe once a day now it’s most of the time. I check the batteries, connections, grounds, etc. awhile back I had no response to pedal at all so change the pedal sensor. It does not log any codes. I have checked EUP connections also. Any advice would be greatly appreciated 

Ok thanks for that input I know I have a few small leaks because next morning I only have about 40 lbs in tanks but just recently my purge valve is popping off every 20-30 seconds